Pneumatic concentrating-table.



0, Q. PAYNE. PNEUMATIC GONGENTRATING TABLE.

APPLICATION FILED AUG. 14, 1912.

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2 BHEETB-SHEET 1.

On Q. PAYNE. PNEUMATIC GONOENTRATING TABLE.

APPLIUATION FILED AUG. 14, 1912.

Patented July 22, 1913.

2 SHEETS-SHEET 2.

3Z3 t MCWOW 213 S CLARENCE Q. PAYNE, OF NEW YORK, N. Y,

PNEUMATIC CONCENTRATING-TABLE.

Specification of Letters Patent.

Patented July 22, 1913.

Application filed August 14, 1912. Serial No.'715,006.

To all whom it may] concern:

lie it known that l, CLAunNcn Q. PAYNE, a citizen of the United States of America, residing in the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in Pneumatic Concentrating-Tables, of which the following is a full and true description.

My invention relates to improvements in that type of concentrating table which separates crushed ores, and other mineralv aggro gatcsin a dry state, by reason of differences in the specific gravity of their associated minerals, when they are acted on by air under pressure, while being subjected to mechanical agitation.

ltembraces a novel and more durable medium for the tabletop than any heretofore employed for this purpose. This medium consists preferably of plates of accreted mineral particles forming a porous mineral septum, which while oifering resistance to the passage of material through it, is permeable to air. It is also resistant to abrasion from material passing over it, and is especially adapted to the treatment of material in a fine state of division, and also of material which has been heated in drying it. By my invention the table-top is also utilized to equalize and control the air-pressure as it passes through it. In this way the air-pressure is enabled to act uniformly over a large area, thus securing more efiicientresults in separation.

In the accompanying illustration, Figure 1 shows in cross-section a view through a table-top, in which a novel medium for the latter is used: viz., porous silica plates or a similar mineral septum, through which air is made to pass. Figs. 2, 3, 4i, 5 and 6 show the application of my invention to two different types of concentrating tables.

It has heretofore been customary to use for the pervious top of pneumatic concentrating tables, some form of textile material, such as single or double woven cotton cloth, through which the air under pressure is made to pass, in order to permeate and agitate the ore-mixture which is made to travel over its surface, in the process of separating it. Such material, however, while light and inexpensive in first cost, has serious disadvantages. Being much softer than the oreparticles which travel over it, the fibers of the cloth are rapidly cut and abraded, and frequent stoppages and delays for renewal of the top become necessary. Moreover, the openings between the meshes gradually be come choked with fine particles, either from the material passing over the surface of the top, or from impurities contained in the air which is made to pass through it from the under side. This blinding of the clothtop interferes with the proper and uniform action of the air upon the ore-mixture, and thus renders the separation intermittent and diflicult to control.

In my invention I employ porous mineral plates for themedium of the table-top as illustrated in Fig. 1. These plates are preferably made of finely crushed and granular particles of silica fused together with a binder, and left in an open or porous condition either by incomplete fusion, or by the removal of a volatile substance in the process of firing. It is also possible to use other mineral substances, such as natural or artificial pumice, porous clay-brick 0r tiles, etc., the latter more especially for the treatment of fine material, but in general it is desirable to select a material which is harder than the material of the ore-mixture to be treated on it, and which-is not so dense as to require too'great an air pressure in passing the required volume of air through it.

A table-top made up of such plates as I have described may be defined in general terms as a mineral septum. The pores or openings in such a mineral septum are quite irregularly scatteredthrough its mass, and also irregularly connected, so that extremely fine material may be made to travel over its surface without passing through the septum, although the pores may be of greater diameter than the particles resting on it. For the same reason, fine impurities contained in the air delivered to the underside of the mineral septum can be passed through it without choking or blinding the pores.

The porous silica plates arezusually'made about one inch or one and one-half inches thick. The friction a'of the air passing through the irregular pores or passages in the plates causes the latter to act-nib a certain extent as pressure equalizers, so that the air-currents issuing from their upper surfaces are enabled to act upon the oremixture in a uniform manner over a large area. The advantages of a porous mineral septum for the tabletop of a pneumatic'concentrating table are,br1efly, great durability, due to the fact that the principal ingredient is as hard, or harder, than the ore-mixture which is made to travel over it, and is not affected by heat or moisture; absence of choking, or blinding, of the septum, since the pores op passages may be of greater size than the ore particles, and finally, better control over the separation by equalizing and controlling the pressure of the issuing air currents over a large separating area. i

As shown in Fig. 1, the ends of the porous mineral lates may be supported by means of light l irons 33, which are riveted to the frame 12 of the table. Their joints and ends are carefully cemented, so that the air from the box' below the table can only pass through the body of the plates.

' My invention maybe applied to various types of pneumatic concentrating tables. In Fi s. 2 and 3 I have shown its application to a firm of table which covers certain further improvements, whereby the removal of the separated products from the table can be more readily controlled and effected, and which I have made the subject of a separate application for Letters Patent, filed coincidently herewith and bearing Serial Number 715,005, filed August 14, 1912. In this form of table, air is admitted to an inclosed box, 13, below the mineral plates, by means of the pipe 15, which is connected with a pressure fan. The table is supported by hinged levers 11, to the foundation frame 10, and is given an inclination in the direction of its longitiidinal axis, but without transverse inclination, so that an ore-mixture fed at its upper end is allowed to occupy the full width of the table, and is made to travel lengthwise thereof.

p The table is given a rapid reciprocating motion by means of a convenient head-motion mechanism, such as is shown in Figs. 1 and 2. This consists of an eccentric 16,

- which operates toggle levers 17, 17 by means of a pit-man 18, whereby the angle-lever 19, pivoted at 20, moves the connecting rod 21, and with it the table, rapidly back and forth.

The ore-mixture, which should be care- 9 fully sized in advance, may be fed from any convenient hopper, as shown at 2A. As it is caused to travel lengthwise of the table, the

combined effect of the upward air-currents through the fine pores and o enings of the silica plates, or similar minera septum, 'combined with the agitation, due to the shaking motion of the table, causes the minerals of the ore-mixture to separate, and to occupy separate layers or strata on the table top, the

heavy mineral forming the lower layer, while the light gangue mineral forms the upper layer, as lndicated in the sectional view in Fig. ,3. As these stratified minerals reach the lower end of the table, the oresheet is preferably narrowed by the guides 25, 25, so as to thicken the ore-sheet, and to My. invention may also be applied to an other type of concentrating table, as shown in Figs. 4, 5 and 6. In this form the tabletop is given a transverse inclination, with only a slight longitudinal inclination, so that the stratificd products may be separated from each other in thin bands, and then collected at the end and side of the table, as indicated in Fig. 4. Here air is admitted to an inclosed box 10, below the porous mineral plates by means of a pipe 11, which is' connected with a pressure fan. The table is supported by any convenient tilting mechanism, such as shown in Figs. 4: and 5. Here the upper end of the table is held by a hollow shaft 12 in the bracket-support 13 to the foundation frame 14.-. The end of the hollow tates about it, and to which is riveted the spring-plate 16. The latter in turn supports the pin-brackets 17, 17, at its extreme ends, and these fit the ends of the shafts which are held to the frame 18, 18, of the table. The manner in which the ends of the springplate support the table brackets is shown more clearly in Fig. 6.

The bracket 15 has an arm-extension which carries a threaded rod which engages in a nut held as the end of the bracket-arm. By rotating the hand wheel at the end of the rod the bracket 15, and with it the spring plate 16, and the entire table, can be tilted nected with the table by means of the connecting rod 19 operating through the hollow shaft 12. Here an eccentric 20 operates the toggle levers 21, 21, by the pitman-rod 22, whereby the angle-lever 23, pivoted at 24, moves the connecting rod 19, and with it the table, rapidly back and forth, by slightly springing the plate 16. The lower end of .the table may be supported by a singlehinged rocker-arm 25, which permits a forward motion of the table by rotation about the pivot 26, and also a transverse inclination by rotation about the pivot 27. At the same time, a slight vertical adjustment can be secured by the hand-wheel nut and threaded rod 25. The table maybe fed from a convenient hopper, such as that shown at 28, which is placed at'the upper corner of the table. Guide pieces 29, 30 and 31 may be conveniently placed as shown at the upper end of the table, to thicken the ore-sheet, and increase its agitation before it is allowed to fan out over the lower side and end of the table. 7

The action of the air-currents through the porous mineral plates, aided by agitation due to the rapid shaking of the table, causes the minerals in the ore-mixture to stratify, and their separation is then effected by the greater distance the-lower layer, or heavy mineral, travels compared with the upper layer or light mineral, as they are propelled forward over the transversely inclined surface of the table. Their relative positions are indicated by the areas bounded by the broken lines shown in the plan view of the table, Fig, i. The separated products are then collected by guide pieces, whose positions can be adjusted along the end and side of the table, as shown in Fig. 4E.

My invention may also be employed in connection with other types of pneumatic concentrating tables, such as that in which the separation of the stratified minerals of an ore-mixture is effected by superposed diagonal riflies, which guide the separated prgplucts to different sides or positions of the ta e.

Having thus described my invention, I claim:

1. In a pneumatic concentrating table, a porous mineral septum composed of accreted mineral particles in plate form, in combination with means for reciprocatingsaid septum, means for passing air through said porous septum while it is in motion, and means for feeding material to be separated upon the surface of said septum, substantially as described.

2. Ina pneumatic concentrating table, a porous mineral septum composed of accreted mineral particles in plate form, which forms the top of an inclosed box in combination with means for passing air from said box through the porous septum, means for reciprocating said box, and means for feeding material to be separated upon said septum, substantially as described.

3. In a pneumatic concentrating table, the combination of a table-top formed of a 1nineral septum porous to air under pressure, means for feeding the material to be separated upon said tabletop, means for passing air through said porous tablet-op, means for mechanically agitating said table-top in a transversely inclined position, and guides for directing the separated strata of min erals into receptacles at the discharge edges of the table-top, substantially as described.

4. In a pneumatic concentrating table, a

table-top formed of plates of accreted mineral particles, porous to air under pressure, in combination with means for mechanically agitating said table-top while in a transversely inclined position, means for feeding the material to be separated upon said tabletop, means for passing air through said porous table-top, and guides for directingthe separated strata of minerals into'recept-acles at the discharge edges of said tabletop, substantially as described.

. CLARENCE Q. PAYNE. Witnesses:

VVALTER S. J ONES, OLIVER M. PENNINGTON. 

